Drain back flow check



Dec. 24, 1940. F, NEW-[CN 2,225,840 DRAIN BACK FLow CHECK I Filed April 7, 1958 2 shees-sneet 1 BY MM/ ATTORN EY Dec. 24, 1940. F NEWTQN 2225,840

DRAIN BACK FLOW CHECK Filed April 7, 1958 2 Sheets-Sheet 2 ATTORN www Patented Dec. 24, 1940 UNITED sTATEs PATENT OFFICE 2325340 vDRAINA BACK i'Loyv CHECK Frank Newton, Bristol, R. assig'nor to Provi- -dence Steam Trap Company, Inc.,;l,'rovidence,

R. I., a corporation of Rhode Island i Application April 7, 1938, serial Ne. 200,600

I'Claim.

My present invention relates to the plumbing art, and has particular reference to an arrangement for preventing back fiow of liquid and foul airinto trapsor sinks.

It is the principal object of my invention to provide an arrangement for use with trays and sinks positioned at different levels to prevent backing up of fiuid into the trays or sinks at the lower level.

It is an additional object of my invention to provide a simple arrangement which may be manufactured and sold at low cost, and which can be included in new installations, or can be readily inserted in existing installations.

It is a further object of my invention to provide an arrangement for preventing back fiow which can be combined with a trap so as to further seal the tray or `sink against back fiow of foul air.

With the above and other objects and advanl tages in view, my invention consists of a novel arrangement of parts more fully disclosed in the detailed description following, in conjunction with the accompanying drawings, and more specifically defined in the claim appended thereto.

In the drawings;

Fig. l is a perspective view, partly broken away, showing the invention as applied toa tray and a sink at different levels;

Fig. 2 is a plan view of a novel back flow check fitting;

Fig. 3 is a Vertical section therethrough, the

alternative position of the fiap valve being indicated in dotted lines;

Fig. 4 is an end view of Fig. 2, parts being broken away to show the mounting of the fiap Valve;

Fig. 5 is a viewron the line 5-5 of Fig. 3;

Fig. 6 is a sectional detail showing a modified construction;

Fig. 7 is a sectional detail showing a further modified construction; and

Fig. 8 is a sectional detail showing a combination of the modification of Fig. 7, with a trap.

It has been found desirable to provide a back fiow check in the pipe lines connecting a sink and a tray to a drain pipe, the tray being at a lower height, in order to prevent back fiow of liquids and of foul air into the tray. To this end I have provided a novel back fiow check fitting which is positioned in the pipe lines, and has a fiap valve mounted so as to swing downwardly under the influence of gravity so as to close the to ;raypipe 1ine against ntrance of Iiquid and Of foul air. I have further provided modified forms suitable for different types of tray and sink installations, and I have combined a trap therewith so as to maintain the valve in a water seal,

to additionally prevent fiow of foul air upwardlyL 5 to either tray or sink, or both. p i

Referring' to the drawings, the installation designatedl IO includes a sink l I and a tray 2,

the tray being at a lower level than the sink, and

a drain pipe |3 of standard form, the sink Il 10 being connected to the drain pipe by means of a. pipe or conduit I 4 as shown, and the tray having a conduit I 5 as shown. Positioned in the conduts so as to be common to both piping or conduits is a back fiow check fitting IG, see 1 Fig. 2, which includes a generally cylind-rical body portion ll, threaded at its upper inlet end IB and at its lower outlet end |9 and having a lateral inlet branch 20 threaded at its inlet end 2|. A

pivot pin 22, see Figs. 3 and 4, preferably of 20 brass, is mounted in the body l'l in two relatively large clearance passages in spaced bosses 23 so as to provide a mounting for a fiap valve 24, pivotally positioned between the bosses 23,

the fiap valve being preferably of the tongue 25 type and having raised seating portions 25 and 26 which are ground fiat and which respectively cooperate with a seat 21 for the inlet branch 20 and a seat 28 in the body ll, similarly ground fiat whereby downward fiow through either inlet 30 |8 or 2| is freely permitted, but back fiow into the inlet branch 20 is prevented by the free swing fiap branch valve 24. Back fiow from the tray into the sink is also prevented by engagement of the valve With the seat 28. 35

Although the preferred back fiow check fitting is illustrated and described as a T Y type, a twin elbow type fitting may also be used for different installations, as illustrated in Figs. 6, 7 and 8, the twin elbow type fitting comprising a body 40 29 having two branch inlets 30 and 3| which are respectively connected to sinks and trays, and a common outlet 32, the body being provided at its upper end or having mounted in its upper end two pivot rods 33, 34 on which fiap 45 valves 35, 36 are respectively mounted for pivotal swinging, the fiap valves having seating faces 31, 38 for seating engagement with valve seats 39, 40, whereby back fiow of liquids or gases from the drain pipe er either inlet into the other 50 inlet is effectively prevented by engagement of the valves 35 and 36 with their respective seats under the infiuence of the weights of the valves. Instead of using two separate valves 35 and 36 which respectively seal each inlet, a common valve may be provided to prevent back flow into one inlet, this construction being illustrated in Fig. 7, in which the bodyV is of twin elbow shape, and has two inlets 4| and 42 and a common outlet 43, the body having la single pivot pin 44 mounted thereon on which is swingingly mounted a fiap valve 45 having seating lsurfaces 46 and 41 which are adapted to seat on valve seats 48, 49, associated with the inlets 4`| Vand 42. In this construction; the fiap valve'45 normally hangs vertically downward, but will prevent cross flow from either inlet into the other.

If desired, a further seal can be obtained, note Fig. 8, by eonnecting the outlet 43 with a trap construction 50, so positioned that the water level is always above the lower end of the flapvalve' 49, whereby a Water seal is obtained for preventing back fiow of foul air into inlet 4| or 42.

The parts are preferably made of cast metal, the flap Valve being of cast metal or of a noncorrodible material, aluminum being preferred because of its lightness, and having its faces ground so as to form perfect contact with the correspondingly ground face or faces of the seat or seats cooperating therewith.

While I have described specific construction embodiments of my invention, it is obvious that changes in thesizes and proportions of the parts, in the relative positioningof the fittings, and in the type of valve arrangements used, may be made to suit the requirements for different installations, without departing from the spirit and the scope of the invention as defined in the appended claim.

I claim:

A drain check fitting comprising a generally cylindrical body having an upper threaded inlet and a lower threaded outlet, a lateral inlet branch entering said cylindrical body having the upper portion of its inner surface sloping gently towards the cylindrical body and the lower portion of its inner surface sloping sharply towards the cylindrical body to provide a communicating oval passageway, said branch having a threaded inlet, the cylindrical body at the injunction of the branch therewith being formed to provide an oval Valve seat inclined towards the cylindrical body axis, the cylindrical body being formed to provide a second oval valve seat extending across the cylindrical body, said body having an integral block provided with a central cut-out and extending inwardly at the intersection of said valve seats, and an oval Valve having integral ears extending inwardly from the Valve body and pivotally mounted in said block cut-out and adapted to seat on either oval valve seat.

FRANK NEWTON. 

